Writing in a BMJ editorial, Finnish researchers argued that efficacy data derived from clinical trials of preventive drugs such as statins and bisphosphonates are not valid evidence of good value for money in reality.

They claimed that benefits seen in carefully controlled trials may not apply in practice. Factors such as age, sex, provider compliance, patient adherence and diagnosis accuracy can all vary in reality.

‘This gap between the ideal and clinical circumstances raises the question of how well our most widely used preventive drugs work in real life,’ they said.

To illustrate the point, authors examined the effectiveness of bisphosphonates in Finland, basing outcomes on entry criteria relevant to clinical trials of the drug.

They estimated that treating all 1.86m citizens aged 50 years and over would prevent only 343 fractures.

‘Thus, although there are claims that important preventive drugs such as statins, antihypertensives, and bisphosphonates are cost effective, there are no valid data on the effectiveness, and particularly the cost effectiveness, in usual clinical care.’

The Finnish researchers said governments and drug approval bodies should promote and fund cost effectiveness trials, and they called for true comparative effectiveness research to become routine.

‘Unless this is done, the important question whether preventive pharmacotherapy is cost effective will remain unanswered.’